[Code of Federal Regulations] [Title 30, Volume 1] [Revised as of July 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 30CFR77.302] [Page 612] TITLE 30--MINERAL RESOURCES CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR PART 77--MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES--Table of Contents Subpart D--Thermal Dryers Sec. 77.302 Bypass stacks. Thermal dryer systems shall include a bypass stack, relief stack or individual discharge stack provided with automatic venting which will permit gases from the dryer heating unit to bypass the heating chamber and vent to the outside atmosphere during any shutdown operation.